LP:731815 - Crash/valgrind warning Item::send with 5.1-micro

Not repeatable with mysql-5.1.

The following query

SELECT CONVERT_TZ( TIMEDIFF( '0000-00-00 00:00:00' , f1 ) , 'UTC' , 'Europe/Moscow' ) FROM t1 ;

causes a crash in Item::send, however GDB does not print a stacktrace. Valgrind reports:

==7458== Thread 3:
==7458== Invalid read of size 1
==7458== at 0x81B33B9: Item::send(Protocol*, String*) (item.cc:5695)
==7458== Address 0x33 is not stack'd, malloc'd or (recently) free'd
==7458==

test case:

CREATE TABLE t1 ( f1 timestamp NULL DEFAULT '0000-00-00 00:00:00');
INSERT INTO t1 VALUES ('2007-06-25 21:00:00'),('2008-03-26 07:09:06');

SELECT CONVERT_TZ( TIMEDIFF( '0000-00-00 00:00:00' , f1 ) , 'UTC' , 'Europe/Moscow' ) FROM t1 ;